Method and apparatus for setting thermostats



Dec. 4', 192s. 1,694,164

D. N.CROSTHWAIT, JR

METHOD AND APPARATUS FOR VSETTING THERMOSTATS original Filed Sept. so,1925 24 snets-sheet 1 Dec. 4, 1928. l 1,694,164

' D. N. CROSTHWAIT, JR n METHOD AND APPARATUS FOR SETTING THERMosTATsoriginal Filed sept. 3o, 1925 '2 Sheetsrsheet 2,

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Patented Dec. 4, 1928.

UNITED STATES 1,694,164 PATENT OFFICE.

DAVID N. CROSTHWAIT, J R., OF MARSHALLTOWN, IOWA, ASSIGNOR TO C. A.D''NHAM COMPANY, OF MARSHALLTOWN, IOWA, A CORPORATION 0F IOWA.

METHOD AND APPARATUS FOR SETTING THERMIOSTATS.

Original application filed September 30, 1925, Serial No. 59,704.Divided and this application led September 10, 1927.

This invention relates to a new and improved method and apparatus forproperly adjusting or setting thermostats in their supporting members,and more particularly for setting the thermostats in thermostatic traps,although it is to be understood that this new method and apparatus isadapted for adjustj ing t-hermostats of different types and in differentinstallations than the one hereafter illustrated by way of example. Thepresent application is a division of my copending application Serial No.59,704, filed September 30, 1925, now Patent No. 1,661,323, `grantedMarch 6, 1928, in which this subjectmatter was first disclosed.

In the type of the-rmostatic traps here under consideration, athermostat comprising a hollow diaphragm member containing a volume ofexpansible fluid is adapted, when heated by surrounding steam, to expandand move a valve against a valve seat and thus cut off the. fiow ofsteam through an outlet passage. lVhen the steam condenses, the coolerwater will contract the thermostat and open the valve allowing the waterof condensation to run out. In assembling the thermostatic disks ordiaphragms, the expansion member is filled with an expansible fluid andwhen cold the vapor pressure in the disk approaches a vacuum. As thethermostat is heated the vapor pressure inside the disk will increaseand Linder operating conditions this internal pressure is a definiteamount in excess of the exterior steam pressure.

The expansion diaphragms used in these thermostats, like all expansibleand contractible containers made of metal, do not expand uniformly whensubjected to the same temperatures, or internal pressures, even thoughmade from the same dies. As a. consequence, the operations of differentthermostats, when installed in the same or similar traps will vary. Inorder to secure uniformlv operating traps, the thermostat should be setso that for a given steam pressure, and

consequent temperature, the thermostat will move the valve disk againstits seat at the limit of its expansion. The effects of variations fromnormal expansion of different thermostats can be eliminated, orcompensated for, if the actual expansion of the disk is measured underactual working conditions, .or under conditions simulating such Workingconditions, and the thermostat set in its sup- Serial No. 218,846.

porting member so as to compensate for the variation from normalexpansion. The new method of setting the thermostats herein disclosedand claimed embodies this principle, and theprincipal object of thisinvention is to provide asimple, accurate, and rapidly operating meansand method of thus setting the thermostats.

In brief, the total expansion or opening of the thermostatic disk isfirst measured under simulated operating conditions. After the disk hasbeen filled with the expansible fluid and sealed, it is assembled or setin a trap top to an approximately correct position, and then itsopening, when cold, is measured by a suitable gauge or indicator. Thesetting of the thermostat is then adjusted to compensate for thedifference between this measured opening and thc actual measured openingof the heateddisk which was determined before it was set in the traptop.

One object of the invention is to provide an improved method for settingthermostats as briefly outlined hereinabove and as described in detailhereinafter.

Another object is to provide an improved means for measuring the totalexpansion of the thermostats under simulated working conditions.

Another object is to provide an improved means for measuring the opening`for which a thermostat is set in its supporting member, that is thedistance that it will have to move or ex and to properly seat the valvecarried there y upon the valve seat in the trap.

Other objectsand advantages of this invention will be apparent from thefollowing detailed description of certain approved forms of apparatusfor carrying out the principles of this invention.

In the accompanying drawings:

Fig. l is a diagrammatic view of a mechanism for measuring the expansionof the thermostat.

Fig. 2 is a plan view of the gauge for measuring the opening for whichthe thermo-- stat has been set in its support.

Fig. 3 is a vertical section, taken substantially on the line 3-3 ofFig. 2.

Fig. 4 is a perspective view of the plate or support which forms a.portion of the adjusting mechanism.

Fig. 5 is a central vertical section through this supporting plate,illustrating the method of adjusting the thermostat in the trap top tocompensate for variations from normal expansion.

Fig. 6 is a central vertical section through an installationillustrating the construction and operation of one of the thermostatictraps which it is the function of this invention to properly adjust.

In Fig. 6 is illustrated a thermostatic steam trap of the type withwhich this invention is directly concerned, although it is to beunderstood that this new method and apparatus is adapted for adjustingand setting thermostats in different installations than hcreillustrated. The casing 1 of this steam trap forms a housing for a steamspace 2, the housing being closed at the top by a cap or top 3 having aflange 4 which screws into the casing. An outwardly extending flange 5on top 3 has a lower surface 6 adapted to Seat closely against the uppersurface 7 of casing 1 when the trap is assembled. The thermostaticmember or disk 8 is of any approved diaphragm type adapted to expandwhen heated, preferably enclosing a volume of volatile liquid forcausing the desired expansion, as is well understood in the art. In thewell-known form here shown, the disk 8 is formed of a pair of opposeddished flexible metallic members joined at their edges, one of themembers being initially provided with a small central opening throughwhich the volatile liquid is inserted. This opening is then plugged andsealed. A stud 9 extending from the center of one diaphragm of disk 8 isadapted to screw into the socket 10 projecting downwardly from cap ortop 3 and thus hold the thermostat in place within the trap. It will beseen that the top 3 constitutes the supporting member for thethermostat, and it is the object of this invention to properly adjustthe thermostat with relation to the supporting top, which may beaccomplished by 'screwing the stud 9 into or out of the socket 10, allas hereinafter described. A valve plate 11 issupported, preferably by auniversal connect-ion 12, from the opposite diaphragm member of disk 8.Vlien the thermostat is expanded, valve plate 11 is adapted to seatagainst the valve seat 13 in casing 1 and close the outlet vpassage 14.Then the thermostat 8 contracts, valve plate V11 will be moved awa fromvalve seat 13 and the passage 14 will e open to allow water ofcondensation to flow from the trap through outlet pipe 15. It will ,beunderstood that the space 2 within the trap is in communicationthrough-lateral extension 16 with a pipe 17 leading from a steam supply,or a space normally filled with steam such as a radiator.

The vertical distance from valve 11 to valve seat 13 when the thermostatis cold and contracted is the opening frequently referred steam at thepressure for which this trap is adapted, the thermostat 8 will expand toits' full extent and seat the plate 11 against valve seat 13. It is thepurpose of this 1nvention to provide a new and improved meth-` od andmeans for adjusting each thermostat 8 in its mounting 3 so that thevalve plate 11 and valve seat 13 will properly cooperate to close thetrap when subjected to normal working temperature and pressure. Asstated hereinabove, the thermostats 8, although made from the same diesand as nearly as possible alike, will not expand equally and it isnecessary to adjust each assembled thermostat and trap top differentlyto insure proper seating of the valve.

Referring now to the apparatus Shown in Fig. 1, a tliermostatic disk 8,before it is filled with the expansible fluid, is mounted as shown withits open side connected by disk adapter 18 with the casing 19 of thetesting apparatus. Casing 19 is in communication through pipe 20controlled by quick opening valve 21 with an exhauster or other sourceof vacuum, and 22 illustrates the connection to a vacuum gauge,preferably of the mercury column type. The dial indicator 23 is mountedon the horizontal arm 24, supported from and vertically slidable along avertical column 25. The dial is bodily adjusted up and down by means ofthe screw 26 which engages a nut in arm 24, the screw being operatedthrough suitable gearingn from the hand wheel 27. The disk 8 is firstexhausted by opening the valve 21, and then the dial f 23 is adjusteddownwardly by means of hand Vwheel 27 until the dial plunger 28contacts.

connected with the supporting means for casing 19. The circuit alsoincludes the battery 32 and circuit breaker or switch 33. Suitableinsulation 34 must be used between the dial supports and the supportsfor casing 19 so that the circuit,can only be completed through the dialand thermostatic disk. After the mechanism is thus adjusted for the zeroexpansion of the disk, fluid under pressure, preferably compressed air,is admitted to casing 19 and thermostat 8 through pipe 35 controlled byquick opening valve 36. The air pressure should be equal to theeffective pressure of the expansible fluid in the disk under normaloperating conditions, this pressure havin-g been previously ascertained23 will now indicate the total Iexpansion or opening7 of thethermostatic disk.

rlhe thermostatic disks as they are tested by this instrument ormechanism will be sorted according to the movement or opening they arefound to have. Each disk having a given opening, within certain limits,will be placed with all other disks having the same opening. The diskswill then be filled with the expansible fluid, exhausted and sealed, butwill be kept sorted. The disks are now to be assembled in the trap tops,and if all of a given sorted class are handled at one time, theapproximately correct setting can soon be ascertained. This approximateopening for which the disk or thermostat is set is now measured by meansof the gauge shown in Figs. 2 and 3. The casing 38 of this gauge has aplurality of spaced projections 39 distributed about the edge of itsopen side and adapted to seat against the surface 6 on outwardlyprojecting flange 5 of the trap top. (See Fig. 3.) A plunger 40 slidablevertically in recess 41 of casing 38 is normally held up against the top42 of the casing by means of a spring 43 which surrounds a stem 44projecting upwardly from plunger 40, the spring being confined betweenthe top of casing 38 and the lock nut 45 mounted on stem 44. The locknuts 45 and adjusting nuts 46 also hold in adjusted position ron stem 44the supporting bracket 47 for the dial indicator 48. Dial test indicator48 is carried by a stem 49, horizontally adj ustable through bracket 47,and the plunger 50 of the dial indicator thrusts against the uppersurface 51 of casing 38. The parts will be so adjusted that in thepositign shown in 3 the indicator will read Zero. The plunger 40 isformed centrally with a projection 52 having a knife edge or series ofprongs 53 which are adapted to Contact with valve plate 11 on thethermostat. The distance from the plane of the endsof projections 53 tothe plane of the ends of the projections 39, (indicated by in Fig. 3),will be equal to the vertical distance from seating surface 7 to thevalve seat 13 of the trap body 1 for which this thermostat is designed,which is also illustrated by in Fig. 6.

When the gauge 38 is assembled over a thermostat and trap top as shownin Fig. 3, it will be apparent that the distance between the. seatingsurface of valve plate 11 and the ends of prongs 53 will be equal to theopening or expansion that the thermostat must have in order to properlyseat when placed in the trap body 1. lVith the assembled thermostat andtrap top in place as shown in Fig. 3, the plunger 40 will be depressedagainst the force of spring 43 until prongs 53 contact with the valveplate 11, and the dial test indicator .48 will then read the opening forwhich the thermostat is set. Preferably this dial indicates the openingin one-thousandths of an inch. This setting is then compared with thepreviously measured opening for that particular thermostat as determinedby the apparatus shown in Fig. 1. The set-l ting of the thermostat inthe valve top must disks then being assembled should have an opening of.O25 of an inch, and when tested by indicator or gauge 38 the dialindicator 48 shows the disk to be set for an opening of .019 of an inch,itwill be apparent that the opening for which the disk is set must beincreased by six thousandths of an inch in order that the thermostat mayoperate properly within one of the traps.

In order to conveniently and expeditiously make this adjustment, themechanism shown in Figs. 4 and 5 is provided. A suitably supported tableor plate 54 is formed with a central opening 55 of a configuration andsize adapted to receive and grip the head 5G of the trap top 3, hereshown as hexagonal in shape. The upper surface of plate 54 is providedwith a graduated dial 57, preferably centered about the opening 55. Theassembled trap top and disk which has just been tested as previouslydescribed,l is positioned with the hexagonal top 56 within the opening55, as shown in Fig. 5. A suitable wrench 58 is now engaged with the nut59 on the base of thermostat 8 and by moving this wrench in onedirection or the other, the stud 9 is screwed in or out of the socket 10in top 3,-whereby the distance between the plane of seat 6, and the seatengaging surface of valve plate 11 may be varied. In the device hereshown, the dial 57 is graduated so that each space on this dialrepresents a vertical adjustment of one one-thousandth of an inch ofvalve plate 11. wrench 58 serves as an indicator for showing the amountof angular adjustment of the thermostat. In the example previouslynoted, the handle 58 would be moved through six divisions of the dial 57in the proper direction to screw the stud 9 further int-o the socket- 10so as t-o increase' the opening for which the thermostatic disk is setby six onethousandths of an inch. The adjusting mechanism justdescribed, and disclosed in Figs.,

4 and 5, has been made the subject matter of and it is claimed in acopending application, Serial No. 218.845, filed September 10, 1927.

By suitably varying the design of the testing and setting devices,`thermostats and mountings of different form or design than that hereshown may be tested and adjusted without departing from the principlesof operation hereinabove described.

The calibrations on the dials23, 48 and 57 need not be in thousandthsof. an inch as de- The handle f scribed, nor need not be exactly asshown in the drawings, it only being essential that these gradiiationsbe in conformity with one another, so that errors indicated on dial 48may be translated into corrections on dial 57.

In another form of therinostatic trap, not

here illustrated, the disk 8 is permanently.

and non-adjustably fixed to the trap top 3, but a screw adjustment isprovided between the valve plate 13 and the tliermostatic disk 8. Itwill be apparent that this form of trap `could be tested and adjusted inexactly the same manner as hereinabove described, the opening beingvaried by adjusting the distance between the valve plate 13 and thethermostatic. disk.

I claim: l

1. The method of adjusting the setting of an expansion thermostat in themember by which-it is supported when in service, which consists in firstdetermining the maximum expansion which the thermostat will haveoperating conditions, then assembling the thermostat with its supportingmember and measuring the opening for which it is temporarily set,determining the difference between this opening and the previouslyascertained expansion ofthe thermostat, and adjusting the settin anamount e ual to this difference so that t e opening wil correspond tothe measured expansion.

3. The method o f adjusting'the setting of an expansion thermostat in.the member b which it is sup rted when in service, whio consists insubjecting the thermostat before assembling it with its lsu portingmember to an internal pressure equa to the maximum to which it will besubjected when in 'service and measuring its ex ansion. under theseconditions, inserting t e volatile expansive fluid, sealing thethermostat, mounting the thermostat-in the member bywhich it issupported when in service and measuring ,the opening for which it istemporarily set, and then adjusting the setting to make the openingcorrespond to the first measured expansion of the thermostat. n

4. The method of adjusting the setting in its supporting member of anexpansion therii'iostat which is adapted to move the valve of expansionwhich the thermostat will have under operating conditions, thenassembling the thermostat between its supporting member and the valveand measuring the opening for which the valve is set with the thermostatcontracted, determining the difference between the opening and thepreviously ascertained expansion of the thermostat, and adjusting thesetting by an amount equal to this difierence so that the opening forwhich it is set will correspond to the first measured expansion.

5. An apparatus for measuring the opening of a thermostat in athermostatic trap, comprising a casing having an open side adapted toreceive the assembled thermostat, valve and trap-top, the trap top beingengaged by the open end of the casing with the thermostat and valveprojecting into the casing, a plunger mounted in the casing in positionto be moved into engagement with the valve, a dial indicator carried bythe plunger, and connections between the dial indicator and the casing,whereby the dial indicator will register the movement of the plunger.

G. An apparatus for measuring the opening of a thermostat in thetherinostatie trap, comprising a casing having an open side adapted toreceive the assembled thermostat, valve and trap-top, the trap top beingengaged by the open end of the casing with the thermostat and ,valveprojecting into the casing, a plunger mounted in the casing in positionto be moved into engagement with the valve, a spring for retracting theplunger, a dial indicator carried by the plunger, and connectionsbetween the dial indicator and the easing, whereby the dial indicatorwill register the movement of the plunger.

7 An apparatus for measuring the opening of a thermostat in athermostatic trap, j

comprising a casing having an open side, aplungerguided for movement inthe casing toward or from the open side, a stem proecting from theplunger through a passage in the closed side ofthe easing, an abutmenton the stem, a spring surrounding the stem. between the casing andthe'abutment for normally holding the plunger in retracted positio,anindicating mechanism vmounted on the stem, and means connecting theindicating mechanism with the casing whereby the mechanism will measurethe movement of the plunger. c

DAVID N. CROSTHWAIT, JR.

